Differential gene expression in Arabidopsis wild-type and mutant anthers: insights into anther cell differentiation and regulatory networks

Authors

  • Asela J. Wijeratne,

    1. Intercollege Graduate Program in Plant Biology, Pennsylvania State University, University Park, PA 16802, USA
    2. Department of Biology and the Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802, USA
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    • Present address: Department of Plant Cellular and Molecular Biology, Plant Biotechnology Center, Ohio State University, 206 Rightmire Hall, 1060 Carmack Road, Columbus, OH 43210, USA.

  • Wei Zhang,

    1. Department of Biology and the Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802, USA
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    • Present address: School of Life Sciences, Shanghai University, Shanghai 200444, China.

  • Yujin Sun,

    1. Department of Biology and the Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802, USA
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  • Wenlei Liu,

    1. Department of Health Evaluation Sciences, Pennsylvania State University, College of Medicine, Hershey, PA 17033, USA
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    • Present address: Global Discovery and Development Stats, Eli Lilly & Company, Indianapolis, IN 46285, USA.

  • Reka Albert,

    1. Department of Physics, Pennsylvania State University, University Park, PA 16802, USA
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  • Zhengui Zheng,

    1. Department of Botany, UF Genetics Institute, University of Florida, 220 Bartram Hall, PO Box 118526, Gainesville, FL 32611, USA
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    • §

      Present address: Department of Zoology, 425 Cancer and Genetics Research Complex. University of Florida, 220 Bartram Hall, PO Box 118526, Gainesville, FL 32611, USA.

  • David G. Oppenheimer,

    1. Department of Botany, UF Genetics Institute, University of Florida, 220 Bartram Hall, PO Box 118526, Gainesville, FL 32611, USA
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  • Dazhong Zhao,

    1. Department of Biology and the Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802, USA
    2. Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, USA
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  • Hong Ma

    Corresponding author
    1. Intercollege Graduate Program in Plant Biology, Pennsylvania State University, University Park, PA 16802, USA
    2. Department of Biology and the Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802, USA
      (fax +1 814 863 1357; e-mail hxm16@psu.edu).
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(fax +1 814 863 1357; e-mail hxm16@psu.edu).

Summary

In flowering plants, the anther contains highly specialized reproductive and somatic cells that are required for male fertility. Genetic studies have uncovered several genes that are important for anther development. However, little information is available regarding most genes active during anther development, including possible relationships between these genes and genetically defined regulators. In Arabidopsis, two previously isolated male-sterile mutants display dramatically altered anther cell differentiation patterns. The sporocyteless (spl)/nozzle (nzz) mutant is defective in the differentiation of primary sporogenous cells into microsporocytes, and does not properly form the anther wall. The excess microsporocytes1 (ems1)/extrasporogenous cells (exs) mutants produce excess microsporocytes at the expense of the tapetum. To gain additional insights into microsporocyte and tapetum differentiation and to uncover potential genetic interactions, expression profiles were compared between wild-type anthers (stage 4–6) and those of the spl or ems1 mutants. A total of 1954 genes were found to be differentially expressed in the ems1 and/or spl anthers, and these were grouped into 14 co-expression clusters. The presence of genes with known and predicted functions in specific clusters suggests potential functions for other genes in the same cluster. To obtain clues about possible co-regulation within co-expression clusters, we searched for shared cis-regulatory motifs in putative promoter regions. Our analyses were combined with data from previous studies to develop a model of the anther gene regulatory network. This model includes hypotheses that can be tested experimentally to gain further understanding of the mechanisms controlling anther development.

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